This study will test a biophysical model of factors hypothesized to contribute to the gender difference in the prevalence of adolescent depression. Attempts to understand depression and the reasons for its increased prevalence for females typically focuses on one of the three major types of variables: cognitive, socio-cultural, or biological. Lack of more comprehensive perspectives integrating these factors obstructs our understanding of this important disorder. The model tested in this project integrates interpersonal, socio-cultural, cognitive and biological variables to explain gender differences in depressive symptoms in late adolescence. Variables include: interpersonal variables of observed behavioral coping during a conflict negotiation task; cognitive variables of negative attributions and perceptions regarding interpersonal relations; socio-cultural variables of personality dimensions commonly assumed as indicators of gender roles and gender socialization; and biological variables of temperament and hypothalamic-pituitary-adrenal axis functioning. Two hundred older adolescents, age 18 to 20 years, will participate in the study along with their romantic partner (total N = 400). The study has a short-term longitudinal design, enabling examination of the relevance of the variables to existing symptomatology and diagnoses as well as to trajectories of change in symptoms and diagnoses over a 6-month period. At time 1, couples will complete a variety of self-report measures and interact together in a videotaped conflict negotiation task. Psychophysiological reactions to the interpersonal behavioral coping used in the negotiation task will also be obtained. Psychological symptoms and clinical diagnoses will be assessed at both time 1 and time 2.